1. Field of the Invention
One embodiment of the present invention relates to a semiconductor device and particularly to a storage device and a semiconductor device including the storage device.
2. Description of the Related Art
A metal oxide having semiconductor characteristics, called an oxide semiconductor, has attracted attention as a novel semiconductor. Transistors including oxide semiconductors are under development. For example, Patent Document 1 discloses the structure of a storage element for retaining data at a node that becomes floating by turning off such a transistor.
[Reference]
Patent Document 1: Japanese Published Patent Application No. 2011-171702